Projectile with automatic driving band



June 7, 1932. w, N T 1,861,522

PROJECTILE WITH AUTOMATIC DRIVING BAND Filed May 28, 1931 Patented June 7, 1932 EDGAR WILLIAM BRANDT, OF PARIS, FRANCE rnorncrun wrrn AUTOMATIC *nmvme BAND Application filed May 28, 1931, Serial No. 540,783, and, in France June 16, 1980.

The present invention has for object an improvement in projectiles, in particular in those intended to be shot by means of guns having smooth linings, and which may be charged through the mouth, the said improvement permitting of automatically obtaining tightness of the shooting tube at the moment of fire.

According to the invention, an extensible ring, preferably of deformable elastic or plastic material is located in a groove of appropriate form in the projectile wall which it does not obstruct, but, on the contrary, permits perfect sliding into the gun lining dur- 16 ing charging, the said ring being displaced and being deformed at the begnning of the discharge, under the effect of the gases of the pro elhng charge, which force it tightly against the tube wall in such manner as to Z0 insure a rigorous tightness.

The accompanying drawing shows several examples of attaining the object of this invention.

On this drawing: Fig. 1 is a partial elevation of a projectile with a band according to the invention.

Fig. 2 is an axial section of a detail, on a larger scale, with the band in the position of rest.

Fig. 3 is a view similar to that of Fig. 2, the band being in the working position.

Figs. 4 and 5 are similar views of a modified construction, showing respectively the band in positions of rest and for working.

According to the example of construction represented in Figs. 1 and 2, a driving band, formed by an extensible ring 1, (Figs. 1 and 2) of round section, for example, is located in a groove 2 of the projectile. This groove has a profile chosen in such manner that the displacement of the ring 1 can only be produced by a predetermined force. It may be formed of a single element split or not, or by means of several elements suitably connected together by aid of hooks or in an other manner.

It is possible to utilize for the extensible ring 1, any suitable material, metallic ornot, which is "capableof assuring it the elasticity o and the plasticity desired. Thus,

for examthe wall ple, it may be made of copper, brass, leather, :1 rubber mixture, or even of cotton cord, etc. This ring may, in some cases, be protected against deterioration by a suitable acket or covering preferably constituted by a very thin metal film, applied electrolytically.

There may also, if there is need, be employed independently of this jack or conointly therewith, a layer of material capale of facilitating the sliding, for example, an alkaline soap "diluted in a suitable solvent and applied to the ring or even to the projec tile and specially in the groove.

By way of modification, the ring when of rubber or similarimaterial, may be provided with a jacket formed, for example, by means of a wound metal wire.

When the projectile is introduced into the gun through the mouth, it slides very rapidly into the gun, as the band system permits an appreciable play between the zone of greatest diameter of the projectile and the walls of the tube. This feature permits, in case of need, a considerable increase in the rapidity of fire.

At the beginning of the discharge, under the pressure of the gases, the ring 1 is forced upward in the groove 2 and is deformed and expanded in the course of its displacement by reason of the peculiar form of the groove, and comes to bear bet-ween the .wall 3 of the tube and the wall 4 of the projectile (Fig. 3). It thus assures the desired tightness and at the same time produces an automatic cleaning of the lining.

A ring 1 of rectangular section may also be.employed, for example, of rubber, located in a groove 2 of corresponding form as shown in Fig. 4. At the beginning of the discharge, the gases from the powder exert upon the lower face of the ring 1 an increased pressure at'the moment when the pressure prevailing between the outer face of the ring and 3 of the shooting tube is diminished by the increase of the velocity of the gases. Consequently, the ring 1, being compressed in the direction of height, is expanded in diameter and comes to bear between the wall 3 of the tube and the wall 4 of theprojectile (Fig. 5) and thus assures the desired tightness and the cleaning of the lining as in the preceding case.

Experience has shown that the band according to this invention assures not only, with an equal charge, a considerable increase in the distanceof trajectory and of accuracy of fire with respect to previous, systems for the same purpose (channels forming pneumatic joints, etc.) but also a large nu ber of other advantages result at the same time from the nature and the method of operation of the band.

Thus, for instance, the flexibility of its operation permits compensating for the variations of longed rapid firing and assures, consequently, the maintenance of distance of trajector from beginning to end of a burst of fire of this type, without it being necessary to vary the an le of elevation.

or this same reason, the inconveniences resulting from wear of the lining are eliminated.

In the forms of construction shown, the ring is of lesser normal external diameter than the external diameter of the projectile adjacent the grooves and is expanded outwardly by the pressure form a driving band by engagement between the projectile and gun walls. In each instance, the ring is originally of lesser cross section than the cross section of the groove. In each instance, the ring is located toward the front or point side of the rear wall of the groove in such manner as to provide a space into which the powder gases may pass for acting upon the rear surface of the ring and cause it to be expanded outwardly. In both illustrations, the rearward or base wall of the groove is comprised, at least in part, of a conical surface.

The employment of this band permits further to increase the tolerances of manufacture of the gun and the projectile, which thus may be made directly by casting. Especially in case that the projectile is made by casting as cups, the thin seam or irregular joint corresponding to the line of connection sf the two cups may come at the groove 2.

Thus the machine work is reduced to a minimum and thus also the cost price.

In:the forms shown, the projectile is of double-ogival form and its body portion has a maximum diameter at a point intermediate the ends, from which it decreases in both directions toward front and rear, while the groove is located substantially at the point of maximum diameter.

It is self evident that the examples of construction above are only given purely by way of explanation and not of limitation and that various modifications of detail may be made without departing" from the scope of the invention.

claim:

1. A projectile intended to be fired from a caliber arising in the gun by a proof the powder gases smooth bore gun, comprisin a bod portion of lesser diameter than the re whereby it is adapted to slide freely therein, said body portion having a peripheral groove and a ring of deformable material of lesser external diameter than the external diameter of said body ortion and located in said groove, said ring being of lesser cross-section than said groove and located away from the rear wall thereof to provide a space in which the powder gases may act on said ring to expand it outwardly into engagement between the projectile and gun walls to form a driving band.

2. A projectile comprising two castings in the form of cups, one forming the base and the other the front of the projectile, said cups each having reduced diameters at their abutting surfaces to form a peripheral groove when the castings are connected, means for connecting the. castings together, and a ring of deformable material located in the groove and of lesser or sectional area than said groove and of lesser external diameter than the external diameter of said castings.

3. A projectile intended to be fired from a smooth bore gun, comprising a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and pro vided with a conical wall of a peripheral groove, and a ring of deformable material of lesser external diameter than the externaldiameter of said body portion and located in said groove, said ring being of lesser cross-section than said groove and located away from the rear wall thereof to provide a space in which the powder gases may act on said ring to force it along said conical wall and expand it outwardly into engagement between the projectile and gun walls to form a driving band.

4. A projectileintended to be fired from a smooth bore gun, comprising a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and provided with a conical wall forming the rear of a peripheral groove, and a ring of deformable material of lesser external diameter than the external diameter of said body portion and located in said groove, said ring being of lesser cross section than said groove and located away from said rear wall thereof to provide a space adjacent said conical wall in which the powder gases may act on said ring to expand it outwardly into engagement between the projectile and gun walls to form a driving band.

5. A projectile intended to be fired from a smooth bore gun, comprisin a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and provided with opposed divergent conical walls forming the front and rear of a peripheral groove, and a ring of deformable material of lesser external diameter than the external forming the front diameter of said body portion and located in said groove, said ring being of lesser cross section than said groove and located away from the rear wall thereof whereby to provide a space adjacent said rear conical wall in which the powder gases may act on said ring to force it along said front conical wall and expand it outwardly into engagement between the projectile and gun walls to form a driving band.

6. A projectile intended to be fired from a smooth bore gun, comprising a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and having a peripheral groove, and a ring of asoft nonmetalli-c deformable material of lesser external diameter than the external diameter of said body portion and located in said groove, said ring being of lesser cross-section than said groove and located away from the rear wall thereof to provide a space in which the powder gases may act on said ring to expand it outwardly into engagement between the projectile and gun walls to form a driving band.

7. A projectile intended to be fired from a smooth bore gun, comprising a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and having a peripheral groove, and an extensible ring of soft deformable material having a thin covering of metal thereon and located in said groove, said ring being of lesser normal ex ternal diameter than the external diameter of the projectile adjacent said groove, and being adapted for outward expansion by the powder gases whereby to engage between the pro lizctile and gun walls to form a driving 8. A projectile intended to be fired from a smooth bore gun, comprising a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and having a peripheral groove with a rear wall, an ex tensible ring of deformable material located in said groove and of lesser normal external diameter than the external diameter of the projectile adjacent said groove, said ring bemg located away from said rear wall to provide a space in which the powder gases may act on said ring to expand it outwardly into engagement between the projectile and gun walls to form a driving band, and a soapy coating on said ring and projectile to facilitate the charging of the projectile into the gun and to cleanse the gun bore during discharge.

9. A projectile intended to be fired from a smooth bore gun, comprising a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and having a peripheral groove with a rear wall and a ring of a soft non-metallic deformable material having a thin covering of metal thereon and of lesser external diameter than the exlesser external diameter than the external ternal diameter of said body portion and located in said groove, said ring being of lesser cross-section than said groove and located away from the said rear wall thereof to provide a space in which the powder gases may act on said ring to expand it outwardly into engagement between the projectile and gun walls to form a driving band.

10. A projectile intended to be fired from a smooth bore gun, comprising a body portion of lesser diameter than the bore whereby it is adapted to slide freely therein and having a peripheral groove with a rear wall and a ring of a metallic deformable material (pf body portion and located in said groove,said ring being of lesser cross section than said groove and located away from the said rear wall thereof to provide a space in which the powder gases may act on said ring to expand it outwardly into engagement between the projectile and gun walls to form a driving band.

11. A projectile intended to be fired from a smooth bore gun, comprising a body portion of double-ogival form having a maximum diameter at an intermediate point of its length, said body having a peripheral groove substantially at the point of maximum diam eter, and an extensible ring of deformable material located in said groove and of lesser normal external diameter than the external diameter of the projectile adjacent said groove, said ring being located away from the rear wall of said groove to provide a space in which the powder gases may act on said ring to expand it outwardly into engagement between the projectile and gun walls to form a driving band.

In testimony whereof, I afiix my signature.

EDGAR WILLIAM BRANDT.

ameter of said 

